Only in New Zealand: as a Dutch tourist lay bleeding heavily and shaking from shock after falling down Mt Ngauruhoe, who should come to his rescue but an Olympic gold medallist.

Single sculls champion Mahe Drysdale just happened to be walking the Tongariro Crossing with partner Juliette Haigh and two other rowers on Monday, when they came across Vincent Vos, "who was in a real bad way", Drysdale said yesterday.

"He looked like he had put his back out.

"He couldn't move to get down off the mountain. He was shaking and getting cold."

Vos, 23, told him he was coming down the mountain when he lost control, overbalanced and tumbled forward, cutting himself as he rolled on the steep, scoria-covered slope.

"There was a lot of blood on his arms and back from the grazes. He was pretty worried and in a lot of pain."

So Drysdale rang 111 on his cellphone and stayed with Vos until the Taupo-based Greenlea rescue helicopter arrived.

"We had seen his party further up as we were starting to climb," Drysdale said. "We probably arrived about five minutes after he fell.

"We were able to make him comfortable and warm to get through the shock. By the time the helicopter arrived he was feeling a lot better, his spirits were up and he was talking.

"It was good to see his condition improve by the time the rescue guys reached him. They were awesome."

Even then, Vos' adventures were not quite over. The steep slope made it impossible for the helicopter to land beside him.

Instead, pilot Nat Every lowered Ruapehu Alpine Rescue Organisation crew members Zoe Gilmer and Blake McDavitt to the ground, where they attached Vos to a stretcher slung 110 feet beneath the helicopter. He was flown to flat land nearby, and then on to Rotorua Hospital. He was discharged early yesterday.

Drysdale, who won gold at the London Olympics and is a five-time world champion, was walking the crossing with Haigh, Swedish rower Lassi Karonen and Australian Kim Crow after they all competed in the Billy Webb Challenge on the Whanganui River at the weekend.

Drysdale said he had decided to show Karonen and Crow "a bit of New Zealand".

"We were on our way back from the Red Crater and heading up Mt Ngauruhoe when we came across this guy."

While Drysdale sat with Vos, his three companions continued their climb up the mountain.